Today marks a milestone in India's marathon national election for a new Lower House of Parliament. One-fifth of the 543-seats will be decided. Nationally, the big fight is between the ruling Congress Party and the opposition BJP. But one of the most closely watched contests is in Delhi, where corruption and anti-incumbency are hot button issues.

And as NPR's Julie McCarthy reports, the new AAP, or Common Man Party, could challenge both of the big players.

JULIE MCCARTHY, BYLINE: Delhi offered a breath of political fresh air across the country this winter with the Aam Adami, or Common Man Party, was thrust into power after their upset victory in elections for the local assembly. Mavericks who defined corruption as an impediment to the average Indian's dreams were a hit.

(SOUNDBITE OF MUSIC)

MCCARTHY: But 49 days after taking office, the Common Man's administrators resigned, to contest parliamentary seats, including the seven at play in Delhi. The move alienated many supporters. But the new party's appeal continues for the young generation, like these musicians who sing to get out the vote and volunteers who seek a clean break with traditional parties.

Twenty-one-year-old Gitanjali Agrawal says some representatives from Sonia Gandhi's corruption-tarnished Indian National Congress, and its rival, the main opposition BJP, lack the education to serve.

GITANJALI AGRAWAL: I believe they are experienced in politics. But they are experienced of the dirty politics, dirty politics. And because of Aam Admi Party, I have a dream in my eyes that after ten years when we'll move out of our houses, we'll not be scared.

MCCARTHY: The lack of security for women put Delhi at the epicenter of a global debate about violence against women last year, following the fatal gang rape of a 23-year-old student in Delhi in December 2012.

The main opposition, BJP, has capitalized on the vulnerability many Delhi-ites feel. Take this radio ad...

(SOUNDBITE OF MUSIC)

UNIDENTIFIED WOMAN: (Foreign language spoken)

MCCARTHY: With the daily news of robbery, rape and kidnapping, we wonder if it was a mistake to send our daughter to the city says the worried mother. The public will not forgive those who cannot guarantee security to our daughters, she intones.

But author and analyst Anna Vittacad says, for the first time, all political parties have felt compelled to highlight women's issues.

ANNA VITTACAD: Irrespective of who wins the coming election, we need to make them feel they can lose votes if they don't persist in being sensitive towards women's issues.

(SOUNDBITE OF A CROWD)

MCCARTHY: Here in the Old City of Delhi, commerce is the glue for co-existence. At a time when religious tensions have been raised in the campaign, Hindu, Muslim, and Sikh traders work cheek by jowl linked by time and custom in this unique melting pot.

Eyeglass wholesaler Parvinder Singh Bagga says rising costs and stagnating earnings give him no other option but to try the BJP's Narendra Modi, the chief minister of the State of Gujarat, who has stormed onto the national stage promising to lift India out of it economic doldrums.

PARVINDER SINGH BAGGA: We're not a fan of Modi. We want some change. We are taking a chance if BJP is coming, they'll - maybe he'll give us some alternative. We want some change.

MCCARTHY: Ashok Kumar stands behind the Common Man's Party and its mercurial leader, Arvind Kejriwal, who he says walked off the job because the two main political parties sabotaged his anti-corruption efforts. Kumar focuses on the positive changes that came during the party's short tenure.

ASHOK KUMAR: (Foreign language spoken)

MCCARTHY: My electricity bill used to be about $50. But during that short time my bill came down to $10, he says. Kumar says he is distressed by the beating Kejriwal is taking on the campaign trail, literally. He's has been attacked twice in the past week.

Party spokeswomen Shalini Gupta says they appear orchestrated and blames political opponents.

SHALINI GUPTA: I mean are up against the money muscle power of the established political parties who don't want the system to change for the benefit of the common people.